[CANUFNET] Medians

[Ian Wilson]

I'm looking for information on low-maintenance plant materials and
landscaping designs for road or highway medians that have "stood the
test of time".  I just got a copy of the new "Planning the Urban Forest"
book and saw a photo of an interesting median planting in Urbana,
Illinois utilizing native plants, which got me thinking about what other
cities might be using for medians.
 
The City of Kelowna has been developing more medians in recent years.
We've tried a variety of different designs and plant materials.  Medians
seem to be among the most difficult growing sites in terms of
maintenance and plant health.  Here's some of the challenges that we
have had:
 
1)  Getting enough soil volume for trees and plants, particularly in
narrower medians
2)  Salt spray due to winter road maintenance in our climate.  Some
trees suffer bud dieback due to salt spray.  Others might suffer soil
toxicity once the salts get too high.  One of the best trees we've found
so far seems to be red oak.
3)  Sand accumulations in the planting bed.  Even if you have a nicely
mulched bed, after a year or two it all ends up looking like a bed of
sand.
4)  Worker safety in order to maintain median plant materials and remove
garbage and maintain irrigation etc.
5)  Landscaping medians on highways with higher speeds - the additional
wind and salt spray etc seems to be particularly hard on plants when the
traffic speeds are higher.
 
We have several different designs that we have tried, depending on
situation.  We're starting to move towards a couple of different
designs, one is more of a xeriscape design with trees in a large
planting bed and xeriscape plant ground covers (where we have the
space).  Where speeds are higher and sand and salt accumulation is an
issue we're trying more hardscape with trees in "pits" and hard
surfacing, but unless we use Silva cells or something similar we run
into the challenge of limited soil volumes.
 
Anybody have some good designs or ideas that they'd like to share?
 
thanks, Ian
 
Ian Wilson, RPF, Certified Arborist
Park Services Manager
City of Kelowna
Park Services
Civic Operations
1359 KLO road,
Kelowna, BC  V1W 3N8
iwilson at kelowna.ca
Phone: (250) 469-8842
Fax:  (250) 862-3335
 
 
 
 
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